Another crash happened with 1.0.6g version of RR. This time when IC2 Cropmatron was removed by wrenching it, it immediately crashed the server with: http://pastebin.com/mBNZak3n

The Cropmatron was linked to Wireless Block Extender and WBE was still in place when the Cropmatron was wrenched.

Little update on this. It doesnt seem to be an issue with only Cropmatron. We are currently experiencing a lot of crashes with RR and WBEs. Currently our development server is not able to start and is giving us the same crash log as i posted above. Its becomming quite serious stability issue, and we might start considering removing Refined Relocation from our Modpack, which i really dont want to do, because I love RR. But if players (not only on our server, since the modpack is quite popular on FTB launcher) will start (sorry for the word) "to be annoyed" with these problems, I will need to make appropriate steps :(
Also using the forge config to remove erroring entities is not helping to get the server back up :(

If you need any help with testing RR more thoroughly, I can and will be pleased to help you out.

I think I know what the problem is. IC2 is quite a fast changing mod these days and I have problems with keeping up with all the changes they make. Apparently there has been a change that doesn't seem to want to work right with WBEs. I'll look into this now. If WBEs are too unstable (which is possible, they are quite an 'on the edge of what's possible' block) they can be disabled in the config file (IIRC that will not force-remove all WBEs out of already existing saves).